The authors use an environmental friendly, solvent-free method to prepare metal (II) complexes of cloxacillin and to determine the activity of the complexes. The complexes are more active against the bacteria isolates than the free cloxacillin. The spectral studies showed the cloxacillin (ligand) as monobasic bidentate material that form a complex with metal ion through the carbonyl of amide and carboxylate groups of carboxylic acid, microanalysis results prove that the ligand to metal ratio is 2:1. The researchers recommend the use of solvent-free drugs in the manufacture of metal (II) complexes of active pharmaceutical ingredients to avoid the excessive use of solvents that cause global problems.

New solid-state metal complex of Fe (II) with paracetamol (ligand), that is, [Fe(para)2Cl2] were synthesized mechanically in 1:2 ratio. The complex has been characterized using physicochemical properties and spectral studies. From the IR and electronic spectral studies, the spectra of the complex were different from that of ligand suggesting the formation of coordination compound. Paracetamol was found to be bidentate ligand in which Fe (II) ion coordinated through the oxygen atom of carbonyl of ketone and nitrogen atom of amide in which the complex is assumed to have octahedral geometry. The complex has shown good antimicrobial activities. The solid-state synthetic method is quick and gives a higher yield, without the need of solvent or heating. Its present higher efficiency in terms of materials, time and energy compared to solution-based synthesis. It is therefore, recommended among others that, solid-state synthesis method should be used in the synthesizing drugs with metals.